Flame-proof polycarbonate containing units deriving from halogenated macrocyclic compounds

ABSTRACT

Thermoplastic, branched, high-molecular-weight polycarbonates endowed with flame-proof properties (self-extinguishing properties) are characterized in that they contain in their macromolecule carbonate units, units deriving from a di-hydroxy-aromatic compound having the formula: ##STR1## wherein: R is a single bond; or 
     R is a linear or branched, either substituted or non-substitued, alkylene radical of from 1 to 5 carbon atoms; or 
     R is selected from the group consisting of O, S, SO 2 , CO; 
     X, Y which may be either equal to, or different from, each other, are either H or CH 3  ; 
     m, n which may be either equal to, or different from, each other, are integers comprised within the range of from 1 to 4; 
     and units deriving from a halogenated macrocyclic compound having the formula ##STR2## wherein: R 1  is H or OH or chlorine or bromine, and 
     R 2  is chlorine or bromine.

This is a divisional of application Ser. No.: 07/371,513 filed June 26,1989, now U.S. Pat. No. 4,987,269.

The present invention relates to thermoplastic, branched,high-molecular-weight polycarbonates endowed with flame-proofproperties.

The polycarbonates are renown in the art thanks to their excellentphysical and mechanical properties such as, e.g., their high impactstrength and their considerably high dimensional and thermal stability.

Owing to the more and more increasing need of having available materialswhich, due to safety reasons, are also endowed, besides excellentmechanical properties, with flame-proof properties, in the art severalmethods have been developed in oder to endow polycarbonates withself-extinguishing properties.

One among the most commonly used methods is based on the introduction ofhalogens, mainly bromine and chlorine, into the polycarbonate.

The halogens can be introduced into the polymer as additives, withgenerally polyhalogenated organic substances being used, such asdisclosed, e.g., in U.S. Pat. No. 3,357,942, together, if desired, withfurther additives showing a synergistic action, such as, e.g., antimonyoxide (J. T. Howarth et al. Plastic World, March 973, pages 64-74).

Binding halogens to the polymeric chain by using difunctional phenols,such as, e.g., tetrabromobisphenol-A and tetrachloro-bisphenol-A, ascomonomers in the preparation of the same polycarbonate, is known (U.S.Pat. No. 3,334,154).

The halogenated substances known from the prior art, whether they areadditives, or monomers to be incorporated into the polymeric chain, haveanyway to be used in rather considerable amounts, in order to be capableof endowing the polycarbonate with the desired self-extinguishingproperties.

If on one hand the presence of considerable amounts of halogens in thepolycarbonates endows the same polymer with flame-proof characteristics,on the other hand it causes a degradation of the polycarbonate duringthe processing steps, thus causing a decay of the physical andmechanical characteristics typical of non-halogenated polycarbonate.

Furthermore, the high temperatures required for the processing of thepolycarbonate may cause the degradation of the halogenated compounds,and the development of hydrogen halide acids, with consequent damagingof the machinery by corrosion.

Therefore, the unsolved problem in the art consists in obtainingpolycarbonates endowed with flame-proof properties, which maintainunchanged all of their typical chemical, physical and mechanicalproperties.

The present Applicant has found now that such a problem can be solved,and thermoplastic, branched, high-molecular-weight polycarbonatesendowed with flame-proof properties can be obtained by means of thecopolymerization with a halogenated macrocyclic compound used in smallamounts, anyway smaller than those amounts which cause undesirablechanges to occur in polymer properties.

More particularly, according to the present invention saidpolycarbonates are characterized in that they contain in theirmacromolecule carbonate units, units deriving from a di-hydroxy-aromaticcompound having the formula: ##STR3## wherein: R is a single bond; or

R is a linear or branched, either substituted or non-substituted,alkylene radical of from 1 to 5 carbon atoms; or

R is selected from the group consisting of O, S, SO₂, CO;

X, Y which may be either equal to, or different from, each other, areeither H or CH₃ ;

m, n which may be either equal to, or different from, each other, areintegers comprised within the range of from 1 to 4;

and units deriving from a halogenated macrocyclic compound having theformula: ##STR4## wherein: R₁ is hydrogen or OH or chlorine or bromine,and

R₂ is chlorine or bromine.

In order that said polycarbonates may show flameproof properties, it isenough that in their macromolecule they contain from 0.05 to 5 units,and preferably from 0.05 to 2 units, deriving from (II) per each 100units deriving from (I).

Some examples of dihydroxy-aromatic compounds (I) which can be used arethe following:

4,4'-dihydroxy-diphenyl;

2,2-bis-(4-hydroxyphenyl)-propane (bisphenol-A);

2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane;

bis-(4-hydroxyphenyl)-methane.

The polycarbonates according to the present invention can also containunits deriving from compounds containing one single aromatic, divalentring, such as, e.g., resorcinol and hydroquinone.

The halogenated macrocyclic compounds complying with formula (II) arenovel compounds and can be prepared by means of the condensation ofresorcinol with a derivative of benzaldehyde having the formula:##STR5## wherein: R₁ is hydrogen or OH or Cl or Br;

R₂ is either Cl or Br.

The reaction is catalysed by acids, and generally a mixture is used ofsulfuric acid and acetic acid, which acts both as a catalyst and as thesolvent.

The molar ratio of resorcinol to (III) should be of at least 1:1. andpreferably an excess of resorcinol relatively to said ratio is used.

The temperature at which the reaction is carried out is of the order of5°-10° C., and from 4 to 40 hours are necessary in order that thereaction may proceed up to completeness. The macrocyclic compound isfinally recovered by precipitation in water.

Some examples of halogenated macrocyclic compounds suitable for thepurposes of the present invention are:

2,4-dihydroxy-benzylidene-diphenyl-{4^(I) -chloro-2^(II),4^(II)-dihydroxy-5^(II) -benzylidenediphenyl-[4^(III) -chloro-2^(IV),4^(IV)-dihydroxy-5^(IV) -benzylidenediphenyl-(4^(V) -chloro-2^(VI),4^(VI)-dihydroxy-5,5^(VI) -(4^(VII) -chloro)-benzylidene)]};

2,4-dihydroxy-benzylidenediphenyl-{3^(I),4^(I) -dichloro-2^(II),4^(II)-dihydroxy-5^(II) -benzylidenediphenyl-[3^(III),4^(III)-dichloro-2^(IV),4^(IV) -dihydroxy-5^(IV)-benzylidenediphenyl-(3^(V),4^(V) -dichloro-2^(VI),4^(VI)-dihydroxy-5,5^(VI) -(3^(VII),4^(VII) -dichloro)-benzylidene)]};

2,4-dihydroxy-benzylidenediphenyl-{2^(I) -hydroxy-5^(I)-bromo-2^(II),4^(II) -dihydroxy-5^(II) -benzylidenediphenyl-[2^(III)-hydroxy-5^(III) -bromo-2^(IV),4^(IV)-dihydroxy-benzylidenediphenyl-(2^(V) -hydroxy-5^(V)-bromo-2^(VI),4^(VI) -dihydroxy-5,5^(VI) -(2^(VII) -hydroxy-5^(VII)-bromo)-benzylidene)]}.

The flame-proof polycarbonates according to the present invention can beprepared according to one of the methods of polycondensation reported inthe prior art.

For example, according to the interface polycondensation method, thedihydroxy-aromatic compound (I) is dissolved in an aqueous solution ofsodium hydroxide, and to such a solution an organic solvent immisciblewith water, e.g., methylene chloride, is added, which contains thehalogenated, polyhydroxy, macrocyclic compound (II).

Through the so obtained mixture phosgene gas is bubbled and the reactionis maintained at a temperature comprised within the range of from 15° to25° C. for a time of from 20 minutes up to 6 hours, in the presence of amolecular weight regulator, for example a monofunctional phenol, and ofa phase-transfer catalyst, such as, e.g., a tertiary amine.

The so obtained polycarbonate is isolated by washing the organic phaseaccording to known techniques, and subsequently distilling off thesolvent, or by means of a precipitation with a non-solvent.

According to a preferred form of practical embodiment of the invention,the interface polycondensation reaction is carried out by using, inplace of phosgene, chloroformyl-terminated polycarbonate oligomers(having a molecular weight generally comprised within the range of from400 to 2000), obtained by means of the interface reaction betweenphosgene and a dihydroxy-aromatic compound.

A further possible route in order to obtain the polycarbonates accordingto the present invention consists in the well-known methodology ofsolution polycondensation. In this case, phosgene is bubbled through asolution of methylene chloride and pyridine which contains thedihydroxy-aromatic compound (I), the halogenated macrocyclic compound(II), and a monofuntional phenol as a molecular weight regulator.

Said polycarbonates can be obtained as well by transesterification inthe molten state, by reacting the dihydroxy-aromatic compound and thehalogenated macrocyclic compound with diaryl-, dialkyl- oralkylaryl-carbonates, at a temperature comprised within the range offrom 100° to 300° C., in the presence of transesterification catalysts.

The polycarbonates obtained by means of any of the above disclosedmethods have a molecular weight comprised within the range of from20,000 to 30,000; they maintain unchanged all of the typicalcharacteristics of the thermoplastic materials, and are suitable forbeing processed both by injection-moulding and by extrusion and/orblow-moulding.

Said polycarbonates result to be classifiable as V-0 in fire behaviourtest carried out according to UL 94 Standard (Underwriters'Laboratories, Inc. Bulletin S4) on specimens of 3.2 mm of the thickness,obtained by means of press-moulding or injection moulding.

According to said Standard, the materials receive a rating of V-0, V-1,V-2 on the basis of the results obtained with five specimens, accordingto the following criterion:

V-0: None of the five specimens should show a combution time longer than10 seconds after the flame of a Bunsen burner is removed. The totalcombustion time for all of said five specimens (10 ignitions) should notexceed 50 seconds. None of the specimens should let burning particlesdrip which ignite the surgical cotton placed along the vertical underthe specimen at the distance of 305 mm.

V-1: None of the specimens should show a combustion time longer than 30seconds after the flame of a Bunsen burner is removed. The totalcombustion time for all of said five specimens (10 ignitions) should notexceed 250 seconds. None of the specimens should let burning particlesdrip which ignite the surgical cotton positioned along the verticalunder the specimen, at the distance of 305 mm.

V-2: None of the specimens should show a combustion time longer than 30seconds after the flame of a Bunsen burner is removed. The totalcombustion time for all of said five specimens (10 ignitions) should notexceed 250 seconds. The specimens may burning particles drip whichignite the surgical cotton positioned along the vertical under thespecimen, at the distance of 305 mm.

Furthermore, all of said five specimens should pass the test accordingto UL-94 Standard, otherways they receive their rating on the basis ofthe behaviour of the worst specimen. For instance, if a specimen shows aV-2 behaviour, and the other four specimens show a V-0 behaviour, all ofthe five specimens receive a rating of V-2. Finall, should a specimencontinue to burn for more than 30 seconds after the removal of the flameof a Bunsen burner, it shall not be classified according to UL 94Standard, but will be reported as a "burning specimen".

Furthermore, the specimens are submitted to the fire behaviour testaccording to ASTM D 2863-77 Standard, which correlates the flammabilityof a polymeric material with the concentration of oxygen contained inthe atmosphere under which the same specimen is. This correlation isexpressed by means of the LOI (Limiting Oxygen Index), i.e., as theminimum oxygen percentage capable of maintaining the combustion of thespecimen in an oxygen-nitrogen atmosphere which impinges against thesame specimen by flowing from down upwards.

On the polycarbonates according to the present invention, the followingfurther characterizations were carried out:

Inherent Viscosity (η)

This property is determined in methylene chloride at 20° C. by means ofthe Ubbelhode viscometer and is expressed as dl/g.

Melt Flow Index (MFI)

The evaluation of the melt flow index is carried out on the "meltindexer" on the granulate extruded under a load of 1.2 kg and at thetemperature of 300° C., according to ASTM D 1238 Standard.

Impact Test (IZOD)

The Izod impact test is evaluated on specimens with notch at 0° C.according to ASTM D 256 Standard.

Shear Sensitivity (SS)

The evaluation of this characteristic is carried out on the "meltindexer" on the granulate extruded under loads of 1.2 and 12 kg, at thetemperature of 300° C. according to the ASTM D 1238 Standard.

The following experimental tests are reported for illustrative purposesand should not be intended as being limitative of the purview of thesame invention.

EXAMPLE 1

Preparation of 2,4-dihydroxy-benzylidenediphenyl-{4^(I) -chloro-2^(II),4^(II) -dihydroxy-5^(II) -benzylidenediphenyl-[4^(III) -chloro-2^(IV),4^(IV) -dihydroxy-5^(IV) -benzylidenediphenyl-(4^(V)-chloro-2^(VI),4^(VI) -dihydroxy-5,5^(VI) -(4^(VII)-chloro)-benzylidene)]}["A" Compound); in formula (II): R₁ is Cl in4-position of the aromatic ring: R₂ is hydrogen].

A solution of acetic acid (80 ml) containing 52.8 g (0.48 mol) ofresorcinol and 28.1 ml (0.2 mol) of p-chloro-benzaldehyde is charged toa glass reactor of 500 ml of capacity, equipped with thermometer,mechanical stirrer and cooling jacket.

Into the solution, kept under an inert atmosphere of nitrogen and at thecontrolled temperature of 7° C., 60 ml of a mixture consisting ofsulfuric acid/acetic acid in the ratio of 1:2 by volume is addeddropwise over a time of 30 minutes.

After 24 hours of reaction, the product is recovered by precipitation in3.8 liters of water, filtration, washing with portions of water of 1.5liters each (until the wash liquors reach a neutral pH value), anddrying in oven under vacuum, at the temperature of 120° C., for a timeof 4 hours.

The so obtained raw reaction product is then crystallized in 2.3 litersof acetone by means of solubilization at the boiling temperature of saidsolvent, high-temperature filtration and slow reprecipitation at thetemperature of 0° C.

After filtration, washing with acetone and drying for 3 hours undervacuum at 80° C., 33.6 g of product ("A" compound), equivalent to ayield of 72.2%, is obtained.

The product was characterized as follows:

Molecular weight (VPO): 916 (theoretical value=930)

Melting point (DSC): 406° C.

    ______________________________________                                        Elemental analysis                                                                            C          H     Cl                                           ______________________________________                                        Theoretical values, %:                                                                        67.1       3.9   15.3                                         Found values, %:                                                                              66.9       4.0   14.9                                         ______________________________________                                    

The structure was confirmed by N.M.R. spectroscopic analysis.

EXAMPLE 2

2,4-dihydroxy-benzylidenediphenyl-{3^(I),4^(I) -dichloro-2^(II),4^(II)-dihydroxy-5^(II) -benzylidenediphenyl-[3^(III),4^(III)-dichloro-2^(IV),4^(IV) -dihydroxy-5^(IV)-benzylidenediphenyl-(3^(V),4^(V) -dichloro-2^(VI),4^(VI)-dihydroxy-5,5^(VI) -(3^(VII),4^(VII) -dichloro)-benzylidene)]}["B"Compound); in formula (II): R₁ is Cl in 4-position of the aromatic ring;R₂ is Cl in 3-position of the aromatic ring].

The process is carried out by operating according to the same modalitiesas of Example 1, with 3,4-dichlorobenzaldehyde being used in place ofp-chlorobenzaldehyde.

27 g of "B" compound, equivalent to a yield of 50.6%, is obtained.

The product was characterized as follows:

Melting point (DSC): 416.5° C.

Molecular weight (VPO): 1100 (theoretical value=1068)

    ______________________________________                                        Elemental analysis                                                                            C          H     Cl                                           ______________________________________                                        Theoretical values, %:                                                                        58.4       3     25.9                                         Found values, %:                                                                              58.4       3.2   26.6                                         ______________________________________                                    

The structure was confirmed by N.M.R. spectroscopic analysis.

EXAMPLE 3

Preparation of: 2,4-dihydroxy-benzylidenediphenyl-{2^(I) -hydroxy-5^(I)-bromo-2^(II),4^(II) -dihydroxy-5^(II) -benzylidenediphenyl-[2^(III)-hydroxy-5^(III) -bromo-2^(IV),4^(IV)-dihydroxybenzylidenediphenyl-(2^(V) -hydroxy-5^(V) -bromo-2^(VI),4^(VI)-dihydroxy-5,5^(VI) -(2^(VII) -hydroxy-5^(VII) -bromo)-benzylidene)]};["C" Compound); in formula (II): R₁ is OH in 2-position of the aromaticring: R₂ is Br in 5-position of the aromatic ring].

A solution of acetic acid (205 ml) containing 19.8 g (0.18 mol) ofresorcinol and 30.2 g (0.15 mol) of 2-hydroxy-5-bromo-benzoic aldehydeis charged to a glass reactor of 500 ml of capacity, equipped withmechanical stirrer and thermometer, and dipped in atemperature-controlled bath.

Into the solution, kept under an inert atmosphere of nitrogen and at thecontrolled temperature of 40° C., 45 ml of a mixture consisting ofsulfuric acid/acetic acid in the ratio of 1:2 by volume is addeddropwise over a time of 30 minutes.

After 5 hours, the reaction mixture is precipitated in 4.5 liters ofwater. The precipitate is recovered by centrifugation, is washed threetimes, each time with a portion of water of 1.5 liters (until the washliquors reach a neutral pH value), and is then dried in oven undervacuum, at the temperature of 120° C., for a time of 4 hours.

The so obtained raw reaction product is then crystallized in 250 ml ofpyridine by means of solubilization at the boiling temperature of saidsolvent, high-temperature filtration and low-temperature precipitation.

After filtration, washing with cold pyridine, subsequent washes withethyl ether in order to remove pyridine, and vacuum drying for 4 hoursat 120° C., 34.3 g of product (the "C" compound) is obtained, with ayield of 78.1%.

The product was characterized as follows:

    ______________________________________                                        Elemental analysis                                                                            C          H     Br                                           ______________________________________                                        Theoretical values, %:                                                                        53.2       3.1   27.3                                         Found values, %:                                                                              52.9       3.1   27.1                                         ______________________________________                                    

The structure was confirmed by N.M.R. spectroscopic analysis.

EXAMPLE 4

84 g of bisphenol-A, 1.37 g of "A" compound (equivalent to 0.40% by molrelatively to bisphenol-A), 65.2 g of sodium hydroxide dissolved in 650ml of water, 20 mg of sodium dithionite (as a reducing agent in order toprevent coloured byproducts from forming) and 6.3 ml of an 0.5N aqueoussolution of triethylamine are charged under a nitrogen stream to a glassreactor of 3 liters of capacity, kept at the controlled temperature of25° C.

Then 1.7 g of p-tert.-butylphenol dissolved in 1,300 ml of methylenechloride is added, and 44 g of phosgene gas is bubbled over 30 minutesthrough the mixture with vigorous stirring.

The reaction is continued for 2 hours; at the end, aqueous sodiumhydroxide (at 20% by weight) is added in order to maintain the pH at avalue higher than 11.

At the end, the reaction mixture is diluted with 500 ml of methylenechloride and the organic phase is separated and subsequently washed with300 ml of water (twice), 800 ml of 0.1N hydrochloric acid and, finally,with portions of 600 ml of water, until wash liquors are neutral.

The polymer is recovered by means of the distillation of the organicsolvent; the recovered polymer is dried and ground until a powder isobtained.

The so obtained polycarbonate is then extruded at the temperature of260° C., and the extrudate is then cooled and granulated.

The granules are moulded both by press-moulding (280° C., 50 kg/cm²) andby injection moulding (300° C.), in order to obtain specimens ofdimensions of 127 mm×6.5 mm×3.2 mm.

Five specimens were submitted to fire behaviour test according to UL 94Standard. They result to belong to V-0 class, according to the datareported in Table 1.

The other characteristics of the polycarbonate are reported in Table 2.

EXAMPLE 5

Example 4 is repeated with the same operating modalities and amounts ofreactants, with the exception that 1.5 g of "B" compound is used (0.38%by mol relatively to bisphenol-A) in place of "A" compound.

The so obtained polycarbonate results to be V-0, according to UL 94Standard; the data relevant to the tests carried out is reported inTable 1.

The other characteristics of the polymer are reported in Table 2.

EXAMPLE 6

Example 4 is repeated with the same operating modalities and amounts ofreactants, with the exception that no halogenated macrocyclic compoundsare used.

The so obtained polycarbonate results to be V-2, according to UL 94Standard (see Table 1).

The other characteristics of the polymer are reported in Table 2.

EXAMPLE 7

253.8 g of chloroformyl-terminated polycarbonate oligomers (numberaverage molecular weight=681, chloroformyl end groups=2,758 meq/kg,hydroxy end groups=180 meq/kg), prepared from bisphenol-A and phosgeneand dissolved in 900 ml of methylene chloride, is charged under anitrogen blanketing atmosphere to a glass reactor if 2.5 liters ofcapacity, kept at the controlled temperature of 25° C.

50 ml of water containing 3.0 g of "A" compound (equivalent to 0.27% bymol relatively to bisphenol-A), 5.3 g of p-tert.-butyl-phenol, 5.0 ofsodium hydroxide, 31 mg of sodium dithionite and 7 ml of a 0.05N aqueoussolution of triethylamine is added in the cited order to the abovesolution kept stirred with a double-anchor stirring device running at300 rpm.

40 minutes later 350 ml of water containing 64.4 g of bisphenol-A and20.5 g of sodium hydroxide, and then 115 ml of an aqueuos solution ofsodium hydroxide at 20% by weight are added over a 10-minutes time, byusing a metering pump.

After 140 minutes, the mixture is poured into 3000 ml of methylenechloride; the organic phase is then separated and washed, in the order,with 450 ml of water (twice), 1300 ml of 0.15N aqueous sodium hydroxide(3 times), 900 ml of water (twice), 1300 ml of 0.1N aqueous hydrochloricacid and, finally, with portions of water of 900 ml each, until washliquors are neutral.

The polymer is recovered by distillation of the organic solvent, isdried and ground until a powder is obtained.

The so obtained polycarbonate is then extruded at the temperature of260° C., and the extrudate is finally cooled and granulated.

The granules are injection-moulded or press-moulded, in order to obtainspecimens of dimensions of (127×6.5×3.2) mm.

Five specimens are submitted to the fire behaviour test according to UL94 Standard, and result to belong to V-0 class, according to the datareported in Table 1.

The other characteristics of the polycarbonate are reported in Table 2.

EXAMPLE 8

Example 7 is repeated with the same operating modalities and with thesame amounts of reactants, with the exception that 4.4 g of "A" compoundis added (0.41% by mol relatively to bisphenol-A).

The polycarbonate obtained results to be V-0 at the fire behaviour testaccording to UL 94 Standard (see Table 1).

The other characteristics of the polymer are reported in Table 2.

EXAMPLE 9

Example 7 is repeated with the same operating modalities and amounts ofreactants, with the exception that 5.1 g of "B" compound is added (0.41%by mol relatively to bisphenol-A) in place of "A" compound.

The polycarbonate obtained results to be V-0 at the fire behaviour test,evaluated according to UL 94 Standard (see Table 1).

The other characteristics of the polymer are reported in Table 2.

EXAMPLE 10

Example 7 is repeated with the same operating modalities and amounts ofreactants, with the exception that no halogenated macrocyclic compoundsare used.

The polycarbonate obtained results to be V-2 at fire behaviour test,evaluated according to UL 94 Standard (see Table 1).

The other characteristics of the polymer are reported in Table 2.

                  TABLE 1                                                         ______________________________________                                               Total combustion time                                                                        Total combustion time                                          of 5 specimens per specimen   UL-94                                           (10 ignitions) (2 ignitions)  classi-                                  Example                                                                              (seconds)      (seconds)      fication                                 ______________________________________                                        4      37             8              V-0                                      5      42             9              V-0                                      6      122            29             V-2                                      7      39             10             V-0                                      8      26             8              V-0                                      9      38             9              V-0                                      10     142            25             V-2                                      ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                                               Impact                                                        [η] 20° C.                                                                         strength                                                                             MFI    SS                                              CH.sub.2 Cl.sub.2                                                                      LOI    (IZOD) (300° C.,                                                                     (300° C.;                         Example                                                                              (dl/g)   %      (J/m)  1.2 kg)                                                                              1.2 and 12 kg)                           ______________________________________                                        4      0.587    34     762    4.1    19.7                                     5      0.590    32     743    3.9    20.0                                     6      0.520    26     732    7.6    13.7                                     7      0.578    33     767    4.0    20.0                                     8      0.599    35     790    3.1    21.8                                     9      0.569    36     800    4.2    19.8                                     10     0.516    26     778    8.6    13.2                                     ______________________________________                                    

I claim:
 1. A thermoplastic, branched high-molecular-weightpolycarbonate having flame-proof properties comprising units from adi-hydroxy-aromatic compound having the formula: ##STR6## wherein: R isa single bond; orR is a linear or branched, either substituted ornon-substituted, alkylene radical of from 1 to 5 carbon atoms; or R isselected from the group consisting of O, S, SO₂, CO; X,Y which areeither equal to, or different from, each other, are either H or CH₃ ;m,n which are either equal to, or different from, each other, areintegers comprised within the range of from 1 to 4;and units from ahalogenated macrocylic compound having the formula: ##STR7## wherein: R₁is hydrogen or OH or chlorine or bromine, and R₂ is chlorine or bromine.2. A polycarbonate according to claim 1, comprising from 0.05 to 5 unitsfrom (II) per each 100 units from (I).
 3. A polycarbonate according toclaim 2, comprising from 0.05 to 2 units from (II) per each 100 unitsfrom (I).
 4. A polycarbonate according to claim 1, wherein thedihydroxy-aromatic compound (I) is selected fromamong:4,4'-dihydroxy-diphenyl; 2,2-bis-(4-hydroxyphenyl)-propane;2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane; andbis-(4-hydroxyphenyl)-methane.
 5. A polycarbonate according to claim 1,wherein the halogenated, poly-hydroxy macrocylic compound (II) isselected from among:2,4-dihydroxy-benzylidenediphenyl-(4^(I)-chloro-2^(II),4^(II) -dihydroxy-5^(II) -benzylidenediphenyl-(4^(III)-chloro-2^(IV),4^(IV) -dihydroxy-5^(IV) -benzylidene-diphenyl-(4^(V)-chloro-2^(VI),4^(VI) -dihydroxy-5,5^(VI) -(4^(VII)-chloro)-benzylidene))); 2,4-dihydroxy-benzylidenediphenyl-(3^(I),4^(I)-dichloro-2^(II),4^(II) -dihydroxy-5^(II)-benzylidenediphenyl-(3^(III),4^(III) -dichloro-2^(IV),4^(IV)-dihydroxy-5^(IV) -benzylidenediphenyl-(3^(V),4^(V)-dichloro-2^(VI),4^(VI) -dihydroxy-5,5^(VI) -(3^(VII),4^(VII)-dichloro)-benzylidene))); and 2,4-dihydroxy-benzylidenediphenyl-(2^(I)-hydroxy-5^(I) -bromo-2^(II),4^(II) -dihydroxy-5^(II)-benzylidenediphenyl-(2^(III) -hydroxy-5^(III) -bromo-2^(IV),4^(IV)-dihydroxy-benzylidenediphenyl-(2^(V) -hydroxy-5^(V)-bromo-2^(VI),4^(VI) -dihydroxy-5,5^(VI) -(2^(VII) -hydroxy-5^(VII)-bromo)-benzylidene))).